This invention relates to an internal combustion engine and more particularly to an internal combustion engine that has improved idle and low speed running characteristics.
As is well known, the internal combustion engines of an automobile are required to run over a variety of conditions. Because of this, the performance over this range of conditions is frequently a compromise resulting in unsatisfactory performance under certain conditions. One of the more difficult conditions is idle and low load. During this condition, the induction gases pass through the induction system at a relatively low velocity which causes fuel to condense on the internal surfaces of the engine which define the intake passage and which also causes uneven and rough combustion in the combustion chamber. A similar situation prevails at low load conditions. In order to overcome these effects, it has been common practice to run the engine richer than normal at low load and idle conditions. Such rich mixture, however, causes the emission of unwanted exhaust gases. In addition to this defect, such rich mixtures adversely effect the fuel economy of the engine under these running conditions.
It is, therefore, a principal object of this invention to provide an internal combustion engine having an improved induction system for idle and low speed operation.
It is another object of the invention to provide an internal combustion engine having improved idle and low speed running characteristics.
Various devices have been proposed for improving the low and idle running characteristics of the engine. Such devices have been found, however, to significantly add to the cost of the engine, adversely effect the performance under other conditions, or to increase either fuel economy or the emission of unwanted exhaust gas constituents.